Phases and Thermoelectric Properties of Bulk NiSb_2 and Composite of NiSb_2 and CoSb_3 Prepared by Sintering

摘要

For researching the thermoelectric properties, bulk NiSb_2 and the composite of CoSb_3 and NiSb_2 were prepared by sintering. The phases of samples were analyzed by X-ray diffraction and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, Bulk NiSb_2 and the composite of NiSb_2:CoSb_3=2:8 and 4:6 were prepared by sintering at 600°C for 10min and they are N-type semiconductor materials with high densities of 6.998-7.142g/cm~3. The bulk NiSb_2 sample sintered is nearly single phase NiSb_2, while the major phases of the composite of NiSb_2:CoSb_3=2:8 are major phase CoSb_3 with impurity phase NiSb_2. The electric resistivity of bulk NiSb_2 sample increases with temperature rising while those of the composites (NiSb_2:CoSb_3=2:8 and 4:6) increase at 400-500 °C. The absolute values of Seebeck coefficients of the composite samples (NiSb_2:CoSb_3=2:8 and 4:6) increase with temperature rising and are evidently higher than those of bulk NiSb_2. The power factors of the composites (NiSb_2:CoSb_3=2:8 and 4:6) are evidently higher than those of bulk NiSb_2 while the power factor of NiSb_2 sample varies not obviously with temperature rising, but those of the composites (NiSb_2:CoSb_3=2:8 and 4:6) increase with temperature rising and reaches the maximum value of 21.3 10~(-4)Wk~(-2)m~(-1) at 500 °C.